The invention relates to an arrangement for draining off liquid collecting on a ground surface by a drain provided with a frame or a casing and in which for avoiding the penetration of the liquid into the ground, a sealing sheet, film or foil is laid, which extends up to the frame or casing of the drain.
The invention is in the field of draining off rainwater and other liquids from constructions of various types. In connection with roads and squares it is known to collect the liquid at the margins thereof in gutters and to feed it into drains, from where the liquid is drained off underground. The penetration of the liquid into the road body is prevented by a water-repelling surface, e.g. by a bitumen covering layer.
In other constructions, such as e.g., bridges, flat roofs, balconies, etc., it is necessary to reliably prevent the liquid from penetrating below the ground or base surface and special means must be used due to the limited ground depth. It is known to provide a frame or a casing in the foundation or earthwork for draining the liquid and to lay a sealing sheet prior to the application of the covering layer and which extends up to the edge of the frame or the casing. A liquid inlet is then provided in the frame or casing and is oriented at the same height as the covering layer surface.
In connection with a complete sealing by the sealing sheet the disadvantage exists that, on passing from the sheet edge to the edge of the frame, liquid can spread under the sheet and penetrate the foundation, which can be highly disadvantageous if in the case of frost the liquid freezes in the ground and consequently produces cracks.